Adjustable-speed drives are devices commonly used to provide speed control to a motor across a continuous range of possible speeds. This provides much greater equipment flexibility as compared to traditional single speed gearboxes or discrete multi-speed motors. Because of their versatile nature, adjustable-speed drives are increasingly popular for use in a variety of mechanical applications.
A type of adjustable-speed drive relies in part on a combination of a transformer module and a power inverter module. The transformer-module receives a high voltage alternating current (“AC”) stream and lowers the voltage to a usable level. The power inverter module takes the AC stream and converts it to a direct current (“DC”) stream. The adjustable-speed drive may then control the output of the DC stream so as to simulate a wide range of AC output streams. A user may set the desired speed controls and the adjustable-speed drive will adjust the simulated AC output to match the desired speeds.
Transformer modules and power inverter modules are large, heavy pieces of equipment. Accordingly, traditional adjustable-speed drive design only allows for installation of the transformer module and the power inverter module in a side-by-side configuration. In particular, medium voltage adjustable-speed drives are only available for installation as one or more side-by-side modules, having a relatively large footprint. Many plants and operating facilities face significant space constraints. Depending on the location, space may be more limited in either the horizontal or vertical directions. Therefore, a need exists for a medium-voltage, adjustable-speed drive that is capable of meeting the size restrictions of a given location.